Mussel adhesive proteins (MAPs) are remarkable underwater adhesive materials that form tenacious bonds between mussels and the surfaces upon which the mussels reside. During the process of attachment to the surfaces, MAPs are secreted as fluids that undergo a crosslinking or hardening reaction which leads to the formation of a solid plaque. One of the unique features of MAPs is the presence of L-3,4-dihydroxyphenylalanine (DOPA), an unusual amino acid which is believed to be at least partly responsible for adhesion to substrates through mechanisms that are not fully understood. Mussels adhere to a variety of surfaces, including metal, metal oxide, polymers, plastics, and wood.
Control of cell and protein adhesion on surfaces is critical to the performance of biosensors, medical diagnostic products, any instrumentation and assays used requiring handling serum and other human/animal fluids, tissue engineering, localized in vivo drug delivery, implanted medical devices, healing of surgical incisions, adhesion of tissues such as bone and cartilage for healing, and nanotechnology (nanoparticle-based therapies and diagnostic tools). In many industrial applications, control of cellular and protein adhesion to surfaces is also important. Such applications include prevention of mussel attachment to boats and ships, piers, and other structures used in oceans and fresh water, prevention of algal and bacterial growth on water lines used for industrial and drinking water, and sensors used to measure water quality and purity.
In the medical arena, the physical or chemical immobilization of poly(alkylene oxides) (PAO), such as polyethylene glycol (PEG), polypropylene oxide (PPO), polyethylene oxide (PEO), and PEO-PPO-PEO block copolymers, such as those available under the PLURONICS brand name, and polymers such as PEG/tetraglyme, poly(methoxyethyl methacrylate) (PMEMA), and Poly(methacryloyl phosphatidylcholine) (polyMPC) (E. W. Merrill, Ann. NY Acad. Sci., 516, 196 (1987); Ostuni et al., Langmuir 2001, 17, 5605-20, which are incorporated herein by reference) on surfaces has been employed as strategy to limit the adsorption of proteins and cells on surfaces. The methods currently employed to modify surfaces with polymers must be tailored for each type of material, and therefore require different chemical strategies. For example, noble metal surfaces, such as platinum, silver, and gold, can be modified using thiol (—SH) containing molecules, whereas metal oxides are often modified using silane coupling chemistry. No surface modification strategy exists that can be universally applied to different classes of materials. Moreover, many of the current methods rely on expensive instrumentation, complex synthetic procedures, or both.